1. Field of the Invention
The present invention relates to automated material handling and packaging equipment. More precisely, the present invention relates to a method and apparatus for automatically grasping flexible packages and placing them in storage containers for subsequent shipment.
2. Description of the Prior Art and Related Information
Food and beverage industries have employed automated packaging equipment for many years. Typically, the goods to be packaged are held in rigid containers so that the packaging machinery can easily grasp and manipulate each article. An example is in bottling plants where bottles are washed, cleaned, and filled with soda, capped and dispensed into shipping crates, all without much human intervention. Quite often, these machines use pneumatically or hydraulically driven grippers or manipulators that can process large quantities of bottles quickly, and with a minimum of down time. The machines used to package bottles, cans, or similar rigid structures tend to be very large and are usually completely dedicated to the specific task. Primary tasks of these machines include sorting the cans or bottles and arranging them in the proper orientation before they are collected and placed inside shipping cartons. Because the articles to be packaged are protected in a rugged plastic, glass, or metal shell, the handling equipment can be of simpler design and can be more vigorous in operation. No special handling hardware is necessary since the rigid shells are easily gripped by the automated machinery.
On the other hand, especially in the food industry, flexible packages are used to carry liquids, or frangible foodstuff such as potato chips. These flexible packages are more difficult to process and to package because of their soft, pliable exterior and their delicate contents. Indeed, the flexible package is difficult for an automated machine to grasp and handle. Obvious problems include mishandling (e.g., dropping) the soft packages when not enough gripping pressure is used, and rupturing, puncturing or crushing the contents when too much gripping pressure is used. In addition, the flexible nature of the packages results in unpredictable, and amorphous shapes that vary from one package to the next. By contrast, hard shelled articles, like a bottle, have precise dimensions and a uniform exterior that do not change from one bottle to the next in a production line. Hence, the packaging machinery can be of simpler design.
As mentioned above, a common example of where a flexible pouch might be used is in the food industry. There, a machine known as a form-fill-seal machine is used to fill flexible pouches containing frangible consumables such as potato chips, cereals, or fluid matter such as catsup, mustard or the like. Generally, the form-fill-seal machine is a mechanism that dispenses a series of plastic pouches which are indexed into position and filled with the liquid or solid contents. These plastic pouches, called flexible pouches, are then individually heat-sealed by welding the sides of the pouch together and then cut from the other packs. At this stage, the form-fill-seal machine must be unloaded manually using human labor. An attendant must sort through the filled flexible pouches and manually lay the flexible pouches into shipping containers or cases. The process, because of its demand for human labor, is time consuming, inefficient, and expensive.
Although modern pick and place robots have manipulator arms that are capable of performing the same function as a person, the archetypal pick and place robot is a complex machine which does not have high throughput capability. Also, pick and place robots can be expensive, and require sophisticated programming.
Pick and place robots typically are not designed for mass production of flexible articles. Even though the conventional pick and place robot may have vision for shape recognition, and tactile feedback systems coordinated by perhaps some level of artificial intelligence, those features add significantly to the cost of the robot. Moreover, adding a vision system along with a tactile feedback system to the robot may slow down what is already a slow cyclic rate. Therefore, a need presently exists for a method and apparatus for servicing flexible pouches dispensed from, for example, a form-fill-seal machine.